"As we head into colder months with less sun exposure, vitamin D intake from food becomes extremely important. Research shows that low levels of vitamin D may be correlated with abdominal obesity," says Kayleen St.John, R.D., executive director of Nutrition and Strategic Development of Euphebe. "Mushrooms grown under UV light should be incorporated into belly fat-fighting meals." Try this Italian Mushroom and Bean Soup.

"Fructose has (rightly so) gotten a bad rap lately for its role in promoting central obesity or belly fat," says St.John. "However, fructose found in whole foods like fruit does not act so sinisterly in the body. Fresh or frozen raspberries contain a great deal of fiber, which helps to regulate the body's insulin response and also reduce belly fat." If a fresh pint comes with a steep price tag at your local grocer, consider buying 'em frozen: they're cost-effective, last practically forever, and are picked at the peak of freshness.

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Coconut Oil

Fat may have once been villainized as making us pack on the pounds, but the Mediterranean Diet, nutritionist guidelines, and a wide body of research (like this study!) are working to banish fat's former rep. Such is the case bolstered by coconut oil: "Research shows that coconut oil doesn't negatively impact blood lipid levels like once believed and that it may even help to promote a reduction in stomach fat. The belly fat-fighting properties of coconut oil stem from the amount of medium chain triglycerides contained which are metabolized quickly and therefore stand less of a chance to be stored as adipose," says St. John. Simply put: The kind of fats coconut oil contains won't turn into fatty deposits stored in your body.

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Soup

"Research continues to show that enjoying soup before a meal reduces the total caloric load of that meal, which can help banish belly fat," says Julieanna Hever, author of The Vegiterranean Diet. "Filling up on high-fiber foods like a low-calorie soup is so satisfying that you end up eating less overall, thereby reducing weight."

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Artichokes and Asparagus

Like onions and leeks, these green veggies are prebiotic foods that produce acetate, an acid that turns on the fat-burning activity in your cells by helping them recover from inflammation. To get more greens, roast artichoke hearts and asparagus in the oven with olive oil, Parmesan cheese, breadcrumbs, and a spritz of lemon.

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Eggs

"A study published in the International Journal of Obesity compared weight loss after an egg breakfast compared to a bagel breakfast containing similar calories," explains Toby Amidor, R.D., author of The Greek Yogurt Kitchen. "Results founds that participants who consumed two eggs in their breakfast while following a lower-calorie diet lost 65 percent more weight and reduced their waist circumference by 34 percent compared with those who were on a similar calorie bagel breakfast." Eggs are also a great source of protein, which works to keep hunger at bay and curb overeating.

They may not be totally mainstream yet, but there's good reason to incorporate marine gems like nori, hijiki, wakame, arame, and kombu into your regular diet. "With omega-3 fatty acids not found in other plant foods, sea vegetables (or seaweed) are inflammation fighting powerhouses," says St.John. "Omega-3 fatty acids are potent inflammation-fighters, so sea vegetables can enhance your body's ability to suppress inflammation and may lead to a flatter belly." Note: Store-bought seaweed snacks can pack a lot of sodium (which can contribute to bloat), so be sure to scan nutrition labels before purchasing.

"Beans are the ultimate weight loss food," says Hever. "They have the ideal macronutrient composition (a perfect ratio of fiber and protein) to ensure satiety with few calories and they also happen to be versatile, cheap, and user-friendly. You should eat at least one and a half cups of beans a day to support weight loss without feeling hungry."

"Nuts are surprisingly an excellent food to support weight loss. Although they're rich in calories, they've been associated with weight loss and weight loss maintenance," says Hever. "Researchers suggest this is due the fact that nuts promote satiety, thereby leading to compensation of calories elsewhere in the diet. Also, nuts have been shown to increase resting metabolism." A faster metabolism can help flush out any bloating, so this is definitely a plus for slipping into your skinny jeans or favorite cocktail dress.

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Milk

"A study published in study published in Nutrition Journal linked calcium and vitamin D supplementation over 12 weeks with belly fat reduction in obese and overweight college students," says Amidor. "These participants also lowered their calories during this time frame. Although the study was done with supplements, milk is brimming with both calcium and vitamin D, and can be part of a healthy weight loss plan."

Everybody loves their quinoa, but it's time to elevate this less-popular grain to superfood status. "While processed grains and sugar are the main culprits for promoting abdominal fat, whole grains are in another category altogether," says St.John. "Intact grains [i.e., ones that haven't been stripped of their nutrients, as is frequently the case with 'white' options] contain fiber which slows digestion and absorption of the grains, which in turn reduces the amount of insulin released by the body." What does this mean for you? The less insulin your body releases equals less abdominal fat tacking itself onto your tummy.

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Yogurt

To get the most of this natural source of probiotics, seek out yogurts like those by Fage, Dannon, and Oikos, which contain lactobacillus.In a 24-week study published in the British Journal of Nutrition, women who consumed this type of probiotic lost twice as much weight as those who didn't regularly include it in their diets. Besides eating yogurt at breakfast, try using plain or Greek yogurt in chicken or salads in lieu of mayo or sour cream.

It seems counterintuitive to feed the microbiome foods with antimicrobial properties, but studies show that garlic only goes after bad, inflammation-causing bacteria while leaving good bacteria intact. It's also rich in inulin, the fiber that helps the body digest food more efficiently and steadies blood sugar. Add fresh chopped garlic to tomato-mozzarella salads and stir-fries, or sprinkle garlic powder onto meats and fish before grilling.

The traditional hot-dog topping can do serious wonders for your waistline. "Fermented foods like sauerkraut, pickled veggies, and kimchi are some of the best sources of probiotics — a form of good bacteria that support healthy digestion and decrease bloat," says Frank Lipman, M.D., founder of Eleven Eleven Wellness Center in New York City. "That's important, since diets low in probiotics can cause bad bacteria to overtake the good ones, leading to health problems ranging from autoimmune diseases to weight gain."

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Avocado

You know that choosing the right types of fats is key, and here's why: Unhealthy fats, found in processed foods, meats, and cheeses, feed the type of bacteria that spark inflammation and cue your body to store fat, says Lipman. But healthy fats high in omega 3s and 6s — like those in avocado, nuts, olive oil, and salmon — do the opposite. They provide long-burning energy by regulating how quickly glucose enters your cells, keeping hunger at bay. Top a sandwich with mashed avocado, or make a summery side salad with chopped avocado, cherry tomatoes, basil, and lemon juice.

While probiotics encourage the growth of good bacteria, prebiotics feed the ones you already have. When you eat prebiotic foods like onions and leeks, they produce butyrate, a metabolic wonder drug that improves insulin sensitivity and increases the amount of fat you burn, says Rafael Kellman, M.D., author of The Microbiome Diet. Now that it's summer, pop either on the grill to bring out their sweetness. Drizzle with olive oil, salt, and pepper and cook until golden.

This Mexican root vegetable contains inulin, a type of fiber that slows down the absorption of blood sugar to help you feel fuller longer, Kellman says. It's also high in magnesium and manganese, two vitamins needed for digestive enzymes to function at their peak. Add chopped jicama to give salads a nice crunch or shred it in your favorite summer slaw.

Lipman suggests sipping it as soon as you wake up and after each meal. "Bitter foods like lemon help stimulate your body's GI juices and aid the start of the digestion process. When digestion is robust, your body breaks down food better and absorbs more of its nutrients, both of which help you maintain a healthy weight and flat belly." Arugula, dandelion root, and apple cider vinegar will also do the trick, so munch on a salad with these greens before your main course — bonus if it's dressed with cider vinaigrette.

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Leafy Greens

Bok choy, spinach, kale — healthy organisms in the gut, which needs trillions of good bacteria to function at its best, says Lipman. Look for ways to incorporate greens into every meal: Add sautéed kale to scrambled eggs, eat a spinach salad for lunch, and try a stir-fry with bok choy for dinner.

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Kiwi

Craving something sweet? This fruit — along with colorful radishes, tomatoes, and carrots — contains arabinogalactans, a plant-based fiber and prebiotic that feeds the friendly bacteria that help your metabolism function optimally. The fiber also kills E. coli and klebsiella — two types of bad bacteria associated with carrying excess weight, Kellman says. Chop kiwi into grilled chicken salads or purée into smoothies for a colorful and sweet kick.

Having a hearty bowl of oatmeal for breakfast isn't just delicious, it's great for your waistline. "The whole grains not only absorb water to make you feel more full, but they're also high in soluble fiber to keep you feeling satisfied for long periods of time," says Bonnie Taub-Dix, R.D.N., creator of BetterThanDieting.com and author of Read It Before You Eat It. To really prevent any trips to the vending machine between meals, Taub-Dix recommends adding a spoonful of nut butter to your oats.

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Grapefruit

If you have a big-time sweet tooth, grabbing a grapefruit could help cut back on calories from late-night treats. "The interesting thing about grapefruit, and citrus fruits in general, is that they provide an intense, satisfying flavor that rarely gets chanced by sweets," Taub-Dix says. "A grapefruit or citrus fruit after dinner could keep you from reaching for a sweet dessert." Yeah, that's right: a 52-calorie grapefruit can satisfy just as much as a 400-calorie piece of chocolate cake. Sorry, brain, but you just got played.

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Canned Tuna

Canned tuna could be your solution to a flatter belly — and it'll only cost you around 80 cents a pop. "Canned tuna — as well as other fish — is an excellent source of omega-3 fatty acids," Taub-Dix days. "Besides promoting heart health, omega-3s help you ditch pounds by keeping you feeling satisfied while repairing and replenishing muscles." Win-win, much? Instead of making tuna salad with fatty mayo, try Greek yogurt instead. The mix makes the perfect filling for a healthy lettuce wrap or stuffed into an avocado half.

If you're not ready to devour full-on seaweed chunks just yet (you're not alone!), try spirulina. Adding a teaspoon of the pretty blue-green algae into your smoothie every day will help curb cravings, fight illness, and — of course — help you burn off pesky belly fat.

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Chia Seeds

Chia seeds might look small, but they sure are mighty. The tiny seeds can expand 10 times their weight in water, turning into a gel-like substance (chia pudding, anyone?) that can keep you full for longer periods of time, helping you take in less calories overall and lose weight around your midsection.

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Dark Chocolate

It's hard to believe eating a couple pieces of dark chocolate a day can help burn belly fat, but it's true: Researchers in an August 2012 study found adding the sweet treat into your diet can actually promote body weight reduction. Just be sure to grab something that's at least 70% cacao.

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